I use a mac, and I'll be putting together my courses this year in Pages and Numbers, and presenting them with Keynote. Complicated pics I'll be generating with Mathematica, but for the most part it'll be a mac app-only show, which is pleasing me no end. I can't actually start any of this yet though, because I'm too busy looking at my desktop, which changes every minute thanks to a little application called Desklickr, a free app that downloads a random image from Flickr to my desktop and shows it there. It's fascinating what you can see using this system, but it's killed my morning. Between that and Facebook I'm surprised anyone get's anything done at all.
I'll aim to produce a small review of the iWork suite for professors and people interested in teaching, but I'll wait until I've tested the stuff out on the students for a week or two to post it. As von Moltke says, "no battle plan survives contact with the enemy."